In order to cut a moving strand, for instance formed of it a stack of strips of cheese slices, into a succession of pieces it is often necessary to make the cut on the fly, that is while the workpiece strand is moving. So long as the strand is not too tall, this can be done by a quick chopping action in which the blade cuts through the strand and retracts so quickly that the strand does not move appreciably during the cutting operation. The cut will be essentially perpendicular to the strand, producing a piece which has neatly squared ends. If,
If however, the strand is somewhat taller it is impossible to move the blade down through it and then back out fast enough to form a perpendicular cut and not disturb the movement of the strand through the cutting apparatus. At the very least the cut will extend at an acute angle to a perpendicular to the travel direction, the upper and lower ends of the being cut offset by the distance the strand travels between the time the knife enters the top of the strand and the time it cuts through the lower surface of the strand.
Recourse is therefore to a system where the knife moves perpendicular to the strand travel direction on a carriage that itself can move parallel to this direction. The knife is reciprocated vertically and the carriage horizontally in synchronism so that as the knife is cutting through the strand it is moving synchronously with the strand, performing a perfect perpendicular cut.
While such a system is highly effective, the mechanism is fairly complex, in particular with respect to synchronizing the movement of the carriage with that of the knife. This complexity adds to equipment costs and makes the system particularly difficult to clean, something that is a problem with a machine handling foodstuff.